Journal article
Testing hypotheses of speciation timing in Dicamptodon copei and Dicamptodon aterrimus (Caudata: Dicamptodontidae)
Molecular phylogenetics and evolution, Vol.36(1), pp.90-100
2005
Handle:
https://hdl.handle.net/2376/104470
PMID: 15904859
Abstract
Giant salamanders of the genus
Dicamptodon are members of the mesic forest ecosystem that occurs in the Pacific Northwest of North America. We estimate the phylogeny of the genus to test several hypotheses concerning speciation and the origin of current species distributions. Specifically, we test competing a priori hypotheses of dispersal and vicariance to explain the disjunct inland distribution of the Idaho giant salamander (
D. aterrimus) and to test the hypothesis of Pleistocene speciation of Cope’s giant salamander (
D. copei) using Bayesian hypothesis testing. We determined that available outgroups were too divergent to root the phylogeny effectively, and we calculated Bayesian posterior probabilities for each of the 15 possible root placements for this four-taxon group. This analysis placed the root on the branch leading to
D. aterrimus, indicating that current distribution and speciation of
D. aterrimus fit the ancient vicariance hypothesis and are attributable to the orogeny of the Cascade Mountains rather than recent inland dispersal. Furthermore, test results indicate that
D. copei is distantly related to other coastal lineages and likely originated much earlier than the Pleistocene. These results suggest that speciation within the genus is attributable to ancient geologic events, while more recent Pleistocene glaciation has shaped genetic variation and distributions within the extant species.
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Details
- Title
- Testing hypotheses of speciation timing in Dicamptodon copei and Dicamptodon aterrimus (Caudata: Dicamptodontidae)
- Creators
- Craig A Steele - School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USABryan C Carstens - Department of Biological Sciences, University of Idaho, Moscow, ID 83844-3051, USAAndrew Storfer - School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USAJack Sullivan - Department of Biological Sciences, University of Idaho, Moscow, ID 83844-3051, USA
- Publication Details
- Molecular phylogenetics and evolution, Vol.36(1), pp.90-100
- Academic Unit
- Biological Sciences, School of
- Publisher
- Elsevier Inc
- Identifiers
- 99900547092801842
- Language
- English
- Resource Type
- Journal article